Muscle activation patterns during backward walking in people with chronic ankle instability

Area of Science:

• Biomechanics and Motor Control
• Musculoskeletal Rehabilitation
• Gait Analysis

Background:

• Chronic ankle instability (CAI) is associated with altered walking patterns.
• Backward walking (BW) is a recommended intervention for improving locomotion in musculoskeletal disorders.
• Understanding muscle activity during BW in CAI is crucial for effective treatment.

Purpose of the Study:

• To compare muscle activity and activation variability during BW between individuals with CAI and healthy controls.
• To investigate the role of specific leg muscles during BW in CAI.
• To inform rehabilitation strategies for CAI.

Main Methods:

• Surface electromyography (EMG) was used to record muscle activity in peroneus longus, tibialis anterior, medial gastrocnemius, and gluteus medius.
• Participants with CAI and healthy controls performed both BW and forward walking (FW) on a treadmill.
• EMG amplitude (%MVIC) and variability (SD) were analyzed across the gait cycle, with focus on pre- and post-initial contact phases.

Main Results:

• No significant differences in muscle activity amplitude or variability were found between CAI and control groups during BW or FW.
• Both groups demonstrated reduced tibialis anterior and gluteus medius activation during BW.
• Both groups showed increased medial gastrocnemius activation during BW.

Conclusions:

• Muscle activity patterns during backward walking are comparable between individuals with CAI and healthy controls.
• The findings suggest BW may not differentially modulate muscle activity in CAI.
• Results should be interpreted cautiously due to the heterogeneity within the CAI population.